Members of this family are often found in the gene neighbourhood, or fused to, non-ribosomal peptide synthetases.

1: Amidoligases with ATP-grasp, glutamine synthetase-like and acetyltransferase-like domains: synthesis of novel metabolites and peptide modifications of proteins. Iyer LM, Abhiman S, Maxwell Burroughs A, Aravind L; Mol Biosyst. 2009;5:1636-1660. PMID:20023723